It is generally known to use a lightweight composite panel, for example having a honeycomb core arranged between outer cover layers, as a wall element or interior panel element in aircraft cabins. The outer cover layers of the composite panel may comprise laminates of fiber-reinforced synthetic material. The visible outer surface of the wall element may be provided with an essentially acoustically neutral decorative layer, usually in the form of a colored structural film. Various attempts have been made to construct wall elements so as to have a noise attenuating characteristic, and particularly so as to absorb and attenuate noise or acoustic waves impinging upon the outer or visible surface of the wall element, for example from within the interior of the aircraft cabin. Such conventional attempts at noise-attenuating wall panel structures generally include an outer layer that is perforated or otherwise air permeable, so that sound waves can penetrate into the porous interior core of the panel, where the noise is attenuated.
However, it has now been recognized that a substantial portion of the cabin interior noise in an aircraft cabin outfitted with such wall elements is caused by the wall elements themselves vibrating along with the fuselage structure and thus radiating noise into the cabin (structure borne noise). In other words, the noise conducted through the solid fuselage structure as vibrations is also conducted into the wall elements, which thus accordingly vibrate and radiate noise into the cabin. More specifically, the fuselage structure borne noise or vibrations are conducted into the wall elements through the respective attachment or mounting components and are then radiated into the cabin from the outer surface of the respective wall element, which acts as a noise radiating membrane. Any attempts to reduce this noise radiating effect by providing isolation at the attachment or mounting points have very little success, because they are not effective at the proper or critical frequency ranges.